Hi, and welcome.
If you're planning to settle in the UK, the first thing you'll need to think about is getting your wife and her daughter the right to settle there with you. (Short-term visits are OK as the UK doesn't require US citizens to have a visa.) The UK Border Agency website has plenty of info about the conditions that you'll need to meet for that:
UKBA: Husbands, wives and civil partners
One of the conditions is that you'll need to prove that you can support yourselves without help from public funds - so you'll need either a job, or proof of substantial bank balances/income.
Good luck, anyway.
